Add a few symbols for testing.

The lucky ones are: capacitor, resistor and diode.

More symbols can be expected later, when more cairo
functions are exported to Lua and relevant standards
become accessible to me.

share/library/Passive/capacitor.lua

@@ -0,0 +1,38 @@
+-- Symbol name
+names =
+{
+	en = "Capacitor",
+	cs = "Kondenzátor"
+}
+
+-- Render area in base units (X1, Y1, X2, Y2)
+area = {-2, -1, 2, 1}
+
+-- Terminals
+terminals = {{-2, 0}, {2, 0}}
+
+-- Rendering
+render = function (cr)
+	-- The vertical lines
+	cr.move_to (-0.2, -1)
+	cr.line_to (-0.2, 1)
+	cr.stroke ()
+
+	cr.move_to (0.2, -1)
+	cr.line_to (0.2, 1)
+	cr.stroke ()
+
+	-- The contacts
+	cr.move_to (-2, 0)
+	cr.line_to (-0.2, 0)
+	cr.stroke ()
+
+	cr.move_to (0.2, 0)
+	cr.line_to (2, 0)
+	cr.stroke ()
+end
+
+-- Register the symbol
+logdiag.register ("Capacitor", names, area, terminals, render)
+
+

share/library/Passive/diode.lua

@@ -0,0 +1,41 @@
+-- Symbol name
+names =
+{
+	en = "Diode",
+	cs = "Dioda"
+}
+
+-- Render area in base units (X1, Y1, X2, Y2)
+area = {-2, -1, 2, 1}
+
+-- Terminals
+terminals = {{-2, 0}, {2, 0}}
+
+-- Rendering
+render = function (cr)
+	-- The triangle
+	cr.move_to (-1, -1)
+	cr.line_to (1, 0)
+	cr.line_to (-1, 1)
+	cr.line_to (-1, -1)
+	cr.stroke ()
+
+	-- The vertical line
+	cr.move_to (1, 1)
+	cr.line_to (1, -1)
+	cr.stroke ()
+
+	-- The contacts
+	cr.move_to (-2, 0)
+	cr.line_to (-1, 0)
+	cr.stroke ()
+
+	cr.move_to (1, 0)
+	cr.line_to (2, 0)
+	cr.stroke ()
+end
+
+-- Register the symbol
+logdiag.register ("Diode", names, area, terminals, render)
+
+

share/library/Passive/resistor.lua

@@ -0,0 +1,37 @@
+-- Symbol name
+names =
+{
+	en = "Resistor",
+	cs = "Rezistor"
+}
+
+-- Render area in base units (X1, Y1, X2, Y2)
+area = {-2, -0.5, 2, 0.5}
+
+-- Terminals
+terminals = {{-2, 0}, {2, 0}}
+
+-- Rendering
+render = function (cr)
+	-- The rectangle
+	cr.move_to (-1.5, -0.5)
+	cr.line_to (1.5, -0.5)
+	cr.line_to (1.5, 0.5)
+	cr.line_to (-1.5, 0.5)
+	cr.line_to (-1.5, -0.5)
+	cr.stroke ()
+
+	-- The contacts
+	cr.move_to (-2, 0)
+	cr.line_to (-1.5, 0)
+	cr.stroke ()
+
+	cr.move_to (1.5, 0)
+	cr.line_to (2, 0)
+	cr.stroke ()
+end
+
+-- Register the symbol
+logdiag.register ("Resistor", names, area, terminals, render)
+
+